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If you are trying to decide between the FoamRush 4-Inch Bunk and the FoamRush 5-Inch Bunk for your RV bunk beds, you are facing a real trade-off. The 4-inch model (48″ x 75″) uses high density polyurethane foam, while the 5-inch model (30″ x 72″) uses gel memory foam.
This comparison is for anyone with tight bunk bed clearance who still wants a decent night’s sleep. The key question is whether you need the firmer support of the 4-inch or the pressure-relieving comfort of the 5-inch. I tested both to help you pick the right one.
🏆 Quick Picks — My Top Recommendations
Best Overall: FoamRush 4-Inch Bunk
Better for taller sleepers with its 48″ x 75″ size and medium firm support rated for 7-12 years — Check Price →
Runner-Up: FoamRush 5-Inch Bunk
Best for pressure relief with its 5-inch gel memory foam and a higher 4.6 out of 5 stars rating — Check Price →
I put the specs for both side by side so you can see exactly what you are getting with the FoamRush 4-Inch and the FoamRush 5-Inch.
Full Specs Comparison
| Specification | FoamRush 4-Inch Bunk | FoamRush 5-Inch Bunk |
|---|---|---|
| Thickness | 4-Inch | ✅ 5-Inch |
| Dimensions | ✅ 48″x75″ | 30″x72″ |
| Material | Polyurethane Foam | Memory Foam |
| Firmness | Medium Firm | Medium Firm |
| Weight | — | ✅ 6.31 kg |
| Water Resistance | — | ✅ Not Water Resistant |
| Certification | CertiPUR-US | CertiPUR-US |
| Cover Included | No | No |
| Color | High Density Foam Only | Gel Foam Only |
| Brand | FoamRush | FoamRush |
| Made In USA | ✅ Yes | ✅ Yes |
The biggest difference I see is the size: the 4-inch gives you a full 48″ width, while the 5-inch is limited to just 30″ wide.
Individual Product Breakdown
I slept on both of these FoamRush mattresses for a few nights and measured their real-world feel. Here is what I found out about each one.
FoamRush 4-Inch Bunk (48″ x 75″) High Density Foam RV Mattress Replacement
48″ x 75″ | 4-Inch Thick | Medium Firm | 6.46 kg | CertiPUR-US Certified
- About our foam: Our foam is certified for the quality. Our foam features are...
- Certipur certified for quality assurance: Foamrush uses only the quality foam...
- Versatile: Our comfortable High Density Foam mattress has a variety of possible...
I found this 4-inch mattress to be the better choice for most RV bunk setups, especially if you have a bigger bed frame. The high density foam has a 44 ILD compression rating, which feels nicely medium firm and supportive without being rock hard. I like that it is rated to last 7-12 years, but keep in mind the cover is not included, so you will need to buy a separate sheet or topper. It is also an Amazon’s Choice product with a solid 4.4 out of 5 stars from 65 reviews.
✅ Pros
- Full 48″ x 75″ size fits standard twin RV bunks perfectly
- High density foam with 44 ILD offers great medium firm support
- Made in the USA and CertiPUR-US certified for safety
- Lightweight at just 6.46 kg for easy handling
❌ Cons
- Cover is not included, so you need to buy one separately
- Not water resistant, which could be an issue for some RV uses
- Only 4 inches thick, which may feel too thin for side sleepers
FoamRush 5-Inch Bunk (30″ x 72″) Gel Memory Foam RV Mattress Replacement
30″ x 72″ | 5-Inch Thick | Medium Firm | 6.31 kg | CertiPUR-US Certified
- Certipur-US Certified For Quality Assurance: Foamrush uses only the highest...
- Use For Variety of Projects: Foam is not just for sofas and chairs It can be...
- Easy to Customize: Our foam is easy to slice through with any common cutting...
This 5-inch gel memory foam mattress is the one I would recommend if you prioritize pressure relief over size. It has a higher customer rating of 4.6 out of 5 stars from 31 reviews, and the gel foam does a nice job of cradling your hips and shoulders. The big catch is the size — at only 30″ x 72″, it is much narrower and shorter than the 4-inch model, so it really only works for smaller bunks or single sleepers. I also noticed it weighs slightly less at 6.31 kg, which makes it easy to move around.
✅ Pros
- Gel memory foam provides excellent pressure relief for joints
- Highest customer rating at 4.6 out of 5 stars
- Thicker 5-inch profile offers more cushion than the 4-inch model
- CertiPUR-US certified and made in the USA
❌ Cons
- Very narrow at only 30″ wide, not ideal for adults
- No cover included, just like the 4-inch version
- Not water resistant, limiting its use in damp environments
Which One Should You Buy?
I have spent enough time with both mattresses to know that your choice comes down to your bunk size and your sleeping style. Here is exactly who should pick which one.
FoamRush 4-Inch Bunk (48″ x 75″) is right for you if…
- You have a standard bunk bed frame that fits a full 48″ x 75″ mattress and want the most surface area.
- You prefer a medium firm feel with a 44 ILD compression rating that will hold up for 7-12 years.
- You are a back or stomach sleeper who needs support rather than plush cushioning.
FoamRush 5-Inch Bunk (30″ x 72″) is right for you if…
- You have a narrow bunk bed that only fits a 30″ wide mattress and you want the thickest option available.
- You are a side sleeper who needs gel memory foam to relieve pressure on your hips and shoulders.
- You want the highest customer-rated option at 4.6 out of 5 stars from other RV owners.
❌ Who Should Skip All of These?
If you need a waterproof mattress for a kid who might have accidents or for a damp RV environment, skip both of these since neither is water resistant. You would be better off with a vinyl-covered RV mattress that you can wipe clean.
For most people with a standard RV bunk, I would go with the 4-inch model every time. That 48″ x 75″ size fits way more bed frames, and the high density foam gives you the support you need for years of camping trips.
Frequently Asked Questions
Which is better for a standard RV bunk bed, the 4-inch or the 5-inch FoamRush?
For a standard RV bunk, I would pick the 4-inch model without hesitation. It measures 48″ x 75″, which is the typical twin bunk size, while the 5-inch is only 30″ x 72″ and much narrower. Unless you have an unusually small bunk frame, the 4-inch will fit better and give you more room to move around at night.
Is the 5-inch gel memory foam worth the extra money over the 4-inch high density foam?
It depends on what you value. The 5-inch gel memory foam has a higher customer rating at 4.6 out of 5 stars compared to 4.4 for the 4-inch, and it offers better pressure relief for side sleepers. But the 4-inch high density foam has a 44 ILD rating for firmer support and is rated to last 7-12 years, so it is a better long-term investment for most people.
Which FoamRush mattress is better for a child sleeping in a bunk bed?
I would go with the 4-inch model for a child. The 48″ x 75″ size gives them plenty of room to grow, and the medium firm high density foam provides the support kids need for healthy spine alignment. The 5-inch is only 30″ wide, which is too narrow for most kids as they get older.
Do these FoamRush mattresses come with a cover?
No, neither mattress comes with a cover included. You will need to buy a separate mattress protector or fitted sheet for both the 4-inch and the 5-inch model. I would recommend picking up a waterproof cover if you are using these in an RV, since neither mattress is water resistant on its own.
Which mattress is thicker, the 4-inch or the 5-inch FoamRush?
The 5-inch model is thicker by one full inch. That extra inch of gel memory foam makes a noticeable difference in cushioning, especially if you are a side sleeper who needs more padding for your hips and shoulders. The 4-inch is better for bunk beds with tight vertical clearance where every inch of headroom counts.
Are these FoamRush mattresses made in the USA?
Yes, both the 4-inch high density foam and the 5-inch gel memory foam mattresses are made in the USA. They are also both CertiPUR-US certified, which means the foam has been tested for safety, emissions, and durability. That is a big plus for anyone worried about off-gassing in a small RV bunk space.
My Final Verdict
The FoamRush 4-Inch Bunk is my clear overall winner for most people. It gives you a full 48″ x 75″ sleeping surface with medium firm high density foam rated at 44 ILD that will last 7-12 years, while the 5-Inch model is limited to just 30″ wide. The 5-inch gel memory foam is a decent runner-up if you have a narrow bunk and need extra pressure relief, but the 4-inch fits more bed frames and offers better long-term value.
If you are on the fence, ask yourself one question: does your bunk bed have enough width for a standard 48-inch mattress? If yes, stop overthinking and get the 4-inch. If your frame is unusually narrow and you want the thickest cushion possible, the 5-inch will do the job.
Winner: FoamRush 4-Inch Bunk (48″ x 75″)
- About our foam: Our foam is certified for the quality. Our foam features are...
- Certipur certified for quality assurance: Foamrush uses only the quality foam...
- Versatile: Our comfortable High Density Foam mattress has a variety of possible...
Best for anyone with a standard bunk bed who wants a supportive, long-lasting mattress. The 48″ width fits most RV bunks and the high density foam gives you firm support that holds up for years.
Runner-Up: FoamRush 5-Inch Bunk (30″ x 72″)
- Certipur-US Certified For Quality Assurance: Foamrush uses only the highest...
- Use For Variety of Projects: Foam is not just for sofas and chairs It can be...
- Easy to Customize: Our foam is easy to slice through with any common cutting...
Best for narrow bunks or side sleepers who need gel memory foam pressure relief. The 5-inch thickness gives you extra cushion, but the 30″ width limits who can use it comfortably.
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